1. Field of the Invention
The present invention relates to a method for manufacturing a fiber aggregate having the fiber surface which has been given a reforming process. The invention also relates to a liquid supply method that utilizes a fiber aggregate manufactured by such method of manufacture, and an ink supply unit as well.
2. Related Background Art
The ink tank used for an ink jet recording apparatus contains absorber in the tank to keep ink by means of the inner pressure exerted by such absorber, and maintains meniscus stably at the ink discharge portion of a recording head.
As one of ink adsorbents that generate negative pressure in an ink tank of the kind, there is a fiber element that holds ink between entangled fibers by use of capillary force. For this fiber element, the fiber, which is formed by polyorefine resin having polyethylene (PE) formed on the surface layer of polypropylene (PP), is practically used from the viewpoint of recycling capability, as well as the enhancement of wettability with resistance to ink.
On the other hand, the property or character of an object (element) itself is governed by the property of structural material. Conventionally, however, it has been practiced to obtain a desired property of an element by reforming such property of the material on the element surface. As the desired property, there is a reactive group having reactive property such as water-repellency or hydrophilic property or the one that has a reactive group capable of reacting against an additive.
Conventionally, a surface reformation of the kind has been practiced in general is such that the element surface is made radical by use of ozone or UV, or UV and ozone, and that the main compound of a processing agent is formed only by chemical binding.
In contrast, there is the one that obtains a desired property instantaneously by the adhesion to the element surface the processing agent that has such desired property itself without making the element surface radical. However, the resultant effect thereof does not last long.
Particularly, for the hydrophilic processing for the olefine resin which is favorable from the environmental standpoint, there is only known the conventional method for obtaining temporarily an imperfect hydrophilic condition under the presence of liquid by the mixture of surface active agent.
Also, conventionally, there has been used adhesive or primer for forming an additive layer for an element. Among such agents, the primer, such as silane coupling agent, that effectuates only reaction binding on the element surface, needs processing to enable the element itself to react.
As a primer, there is also the type that utilizes the affinity brought about by use of the same material as the target element. As a primer of the kind, acid-denatured chlorinated polypropylene, which is used for giving a coating layer of polyurethane resin to polypropylene as the final coat, is known, but when the same material agent as the element surface should be used, the resultant volume of the target element is increased. Besides, a technique is needed to perform a thin and uniform coating. Also, it is impossible to coat uniformly up to the inside of a fine element or a porous object. Particularly, acid-denatured chlorinated polypropylene is not soluble against water, and cannot be made water soluble. The use thereof is limited accordingly.
It can be stated, therefore, that there is no material, even among those different from the element surface, which can be made water soluble, and usable for a thin and uniform surface reformation irrespective of the configuration of an target element.
The present invention is designed on the basis of the new knowledge acquired during the studies on the criteria of the conventional technology and technique in this respect, and it is an epoch-making one.
With the conventional surface reformation only by means of chemical binding using radical process, a uniform surface reformation cannot be made on the surface having a complicated configuration. Here, in particular, no surface reformation can be effectuated in the inferior of a negative pressure generating member that has a complicated porous portion inside, such as a complex fiber element arranged to generate negative pressure to be used in the field of ink jet technology.
In addition, any method that uses the liquid, in which surface active agent is contained, is not effective in reforming the surface of porous object itself, and when the surface active agent is no longer present, its property is lost completely. The object is allowed to return to the property of the surface itself instantaneously.
Moreover, olefinic resin is excellent in water-repellent property having a contact angle of 80 degrees or more to water, but there is no surface reforming method therefor to make a desired hydrophilic property obtainable for a long time.
Under such circumstances, the inventors hereof have, at first, attempted the surface reformation of olefinic resin rationally, and with the elucidation of a method for maintaining the reformed property thereof, the inventors hereof have arrived at the use of liquid type processing agent after such studies as to provided the surface reforming method which is applicable to every element, while setting it forth as a premise that even the negative pressure generating member formed in a complicated configuration is also a target element that should be made processible.
As a result of assiduous studies for the achievement of the aforesaid objectives, the inventors hereof have proposed a epoch-making method as a hydrophilic processing art as per Japanese Patent Application Laid-Open No. 11-342618.
Here, although the reliability of a final product or a component can be enhanced by means of hydrophilic processing subsequent to having formed such final product or component with a fiber aggregate as the constituent thereof, it is often required to execute a processing step or take a processing time for providing the same property for both the surface area and inner area of such fiber aggregate.